1613-96-3Relevant academic research and scientific papers
Effects of molecular conformation on the spectroscopic properties of 4,4′-disubstituted benzylideneanilines
Fang, Zhengjun,Wu, Feng,Yi, Bing,Cao, Chenzhong,Xie, Xin
, p. 52 - 57 (2016)
The relationship between the molecular conformation and spectroscopic properties of unsymmetrical 4,4′-disubstituted benzylideneanilines, was explored by the combination of experiment and reference data. Crystal structure information and spectroscopic beh
Cooperative catalysis of molybdenum with organocatalysts for distribution of products between amines and imines
Wu, Di,Bu, Qingqing,Guo, Cheng,Dai, Bin,Liu, Ning
, (2021/02/02)
Multi-amino groups and nitrogen donors compound was discovered as an organocatalyst for N-alkylation of alcohols with amines in the presence of Mo(CO)6. The Mo(CO)6/organocatalyst binary system has shown to be a highly active catalyst for the N-alkylation reaction between alcohols and amines with excellent tolerance of variable starting materials bearing different functional groups. Of particular note, this method possessing a superiority selectivity in the synthesis of N-alkylated amines or imines, which can be controlled by the reaction temperature. The cooperative catalysis mechanism in combination of Mo(CO)6 with organocatalyst was elucidated by control experiments.
Insight into the Modes of Activation of Pyridinium and Bipyridinium Salts in Non-Covalent Organocatalysis
Weiss, Robin,Golisano, Tamara,Pale, Patrick,Mamane, Victor
supporting information, p. 4779 - 4788 (2021/09/06)
A series of pyridinium and bipyridinium salts were prepared and their catalytic properties were evaluated in the aza-Diels-Alder reaction between imines and Danishefsky diene. Depending on the substituents of the pyridinium/bipyridinium rings and on the nature of the counterion, two mechanisms of activation were demonstrated. In case of non-substituted rings, the substrate is activated through charge transfer involving the aryl ring on the C-side of the imine. When halogen atoms were introduced on the catalysts, the activation mode switched to halogen bond involving the imine nitrogen lone pair. Moreover, alternative activation modes based on hydrogen bonding and radical cation were ruled out. This work allowed us to develop two families of catalysts whose potential was demonstrated in the cycloaddition of various imines with Danishefsky diene. The first family is composed of the simple methyl pyridinium triflate and dioctyl bipyridinium triflate. The former is active only with imines bearing a p-methoxyphenyl group on the C-side and the latter was found to be efficient with imines bearing different substituents on both the N- and C-sides of the imines. The second family is based on halogenated pyridinium salts which proved active with almost all considered imines. (Figure presented.).
Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
, p. 3843 - 3853 (2021/11/18)
Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
A Highly Selective Manganese-Catalyzed Synthesis of Imines under Phosphine-Free Conditions
Chai, Huining,Yu, Kun,Liu, Bo,Tan, Weiqiang,Zhang, Guangyao
, p. 217 - 226 (2020/01/31)
An efficient and highly selective phosphine-free NN-manganese(I) complex catalyst system was developed for the acceptorless dehydrogenative coupling of alcohols with amines to form imines. The coupling reactions underwent at 3 mol % catalyst loading, and a large range of alcohols and amines with diverse functional groups was applied, including challenging diol and diamine. The target imine products were obtained in good to excellent yields. The present work provides an alternative method to construct highly active nonprecious metal complex catalysts based on phosphine-free ligands.
Synthesis and Reactivity of Fluorinated Triaryl Aluminum Complexes
Ould, Darren M. C.,Carden, Jamie L.,Page, Rowan,Melen, Rebecca L.
supporting information, p. 14891 - 14898 (2020/10/02)
The addition of the Grignard 3,4,5-ArFMgBr to aluminum(III) chloride in ether generates the novel triarylalane Al(3,4,5-ArF)3·OEt2. Attempts to synthesize this alane via transmetalation from the parent borane with trimethylaluminum gave a dimeric structure with bridging methyl groups, a product of partial transmetalation. On the other hand, the novel alane Al(2,3,4-ArF)3 was synthesized from the parent borane and trimethylaluminum. Interestingly, the solid-state structure of Al(2,3,4-ArF)3 shows an extended chain structure resulting from neighboring Al···F contacts. Al(3,4,5-ArF)3·OEt2 was then found to be an effective catalyst for the hydroboration of carbonyls, imines, and alkynes with pinacolborane.
Ruthenium N-Heterocyclic Carbene Complexes for Chemoselective Reduction of Imines and Reductive Amination of Aldehydes and Ketones
Kathuria, Lakshay,Samuelson, Ashoka G.
supporting information, (2020/06/17)
Chemoselective reduction of imines to secondary amines is catalyzed efficiently by tethered and untethered, half-sandwich ruthenium N-heterocyclic carbene (NHC) complexes at room temperature. The untethered Ru-NHC complexes are more efficient as catalysts for the reduction of aldimines and ketimines than the tethered complexes. Using the best untethered complex as a catalyst, electronic and steric demands on the reaction was probed using a series of imines. Chemoselectivity of the catalyst towards imine reduction was tested by performing inter and intramolecular competitive reactions in a variety of ways. The catalyst exhibits a very high TON and TOF under anaerobic conditions.
Micropores Induced Stereoselective Synthesis of E-imines: Synergistic Effect between Cerium Species and Micropores in CeAlPO-5 Molecular Sieves
Jin, Yangxin,Cao, Yali,Fang, Guoyong,Ruan, Fei,Ke, Qingping
, p. 3178 - 3181 (2019/07/04)
Metal-doped zeolitic microporous materials are often viewed as something extremely negative as catalysis for the reactions involving aromatic molecules because of severe diffusion limitation. For these reasons, many chemists aim to development of the large microporous or hierarchical micro-mesoporous zeolites as supports that allow for the access of the “bulky” reactants. But the “small” micropore with respect to an aromatic molecules-involving reaction is not always a negative point. Here we employed a hierarchical micro-mesoporous CeAlPO-5 molecular sieve (HP-CeAlPO-5) as the catalyst that can catalyze stereoselective synthesis of E-imines through the reaction of alcohols with amines. Control reactions, DFT calculations and GC-MS analyses demonstrated that the feature of the uniform “small” micropore in the HP-CeAlPO-5 catalyst play a key role in the stereoselective synthesis of E-imines. In addition, the reaction tolerates a broad range of alcohols and amines, and can be performed with as little as 0.89 mole percent catalyst in more than 90.6 percent yield and about 99.7 : 0.3 stereoselective ratio. This zeolitic catalyst provides a conceptually new and practical protocol to stereoselective synthesis of E-imine compounds.
Phosphine-Free Well-Defined Mn(I) Complex-Catalyzed Synthesis of Amine, Imine, and 2,3-Dihydro-1 H-perimidine via Hydrogen Autotransfer or Acceptorless Dehydrogenative Coupling of Amine and Alcohol
Das, Kalicharan,Mondal, Avijit,Pal, Debjyoti,Srivastava, Hemant Kumar,Srimani, Dipankar
supporting information, p. 1815 - 1825 (2019/04/30)
The application of nontoxic, earth-abundant transition metals in place of costly noble metals is a paramount goal in catalysis and is especially interesting if the air- and moisture-stable ligand scaffold is used. Herein, we report the synthesis of amines/imines directly from alcohol and amines via hydrogen autotransfer or acceptorless dehydrogenation catalyzed by well-defined phosphine-free Mn complexes. Both imines and amines can be obtained from the same set of alcohols and amines using the same catalyst, only by tuning the reaction conditions. The amount and nature of the base are found to be a highly important aspect for the observed selectivity. Both the primary and secondary amines have been employed as substrates for the N-alkylation reaction. As a highlight, we showed the chemoselective synthesis of resveratrol derivatives. Furthermore, the Mn-catalyzed dehydrogenative synthesis of structurally important 2,3-dihydro-1H-perimidines has also been demonstrated. Density functional theory calculations were also carried out to model the reaction path and to calculate the reaction profile.
Halo-1,2,3-triazolium salts as halogen bond donors for the activation of imines in dihydropyridinone synthesis
Kaasik, Mikk,Metsala, Andrus,Kaabel, Sandra,Kriis, Kadri,J?rving, Ivar,Kanger, Tonis
, p. 4295 - 4303 (2019/03/29)
In the past decade halogen bond (XB) catalysis has gained considerable attention. Halo-triazoles are known XB donors, yet few examples detail their use as catalysts. As a continuation of our previous work the catalytic properties of substituted enantiomerically pure halo-triazolium salts were explored in the reaction between an imine and Danishefsky's diene leading to the formation of dihydropyridinone. The catalytic activity of the XB donors was highly dependent on the choice of the halogen atom and on the counterion. Also, it was found that impurities in the diene affected the rate of the reaction.
